As is known from EP 0 753 506 A1, the compound of formula (I) (below) has an analgesic effect and is also used as an intermediate product to produce further analgesic substances. EP 0 753 506 A1 discloses a process for producing the compound of formula (I) starting from a compound of general formula (II),
the production of which is known from the literature (K. Flick et al., Arzneim.-Forsch./Drug Res. 28 (1), issue 1a (1978)), wherein, to convert the tertiary alcohol function on the cyclohexyl radical into a C-substitution with retention on the carbon atom marked by *, thionyl chloride is used as the chlorination reagent and as the solvent. This process therefore requires large quantities of thionyl chloride. The subsequent working up while expelling the excess thionyl chloride with a stream of nitrogen gas or by distillation is stressful for humans, the environment and operating equipment. Furthermore, only poor yields (maximum of 55% of theoretical) are achieved.